Mine was accepted in an hour, on Feb 1st yet still not approved and no deposit date yet. The 21 days is not a promise or guarantee by the IRS or any filing companies or software. It is an estimate only.

Doesn’t happen
IRS will typically ACCEPT your return, will ACKNOWLEDGE its receipt within 24 hours of e-filing
IRS says filers should receive their refund within 21 days of filing: we’re finding most get theirs in about two weeks